“Water” they say is life. The truth to the statement is not farfetched due to various need and importance water is attached to in the area of drinking, domestic, Agriculture and hydroelectric power generation.
Despite the presence of water everywhere in the world, the activities of man craving for better life and comfort in civilization has rendered water that exist in nature on the surface unsafe for consumption due to discharges into water through drainages, streams and rivers to large ocean.
The quest for good and portable water for use in this modern world now gave rise to the use of machines and machineries with high research and development capacity investigation into the earth for water existing beneath the soil surface. The recorded landmark success and proof of presence of abundant water have turned the world scientific interest to groundwater as a resource to replenish and salvage the acute depletion and shortage of surface portable water. Hence, this topic GROUNDWATER RESOURCES.
We shall not take a look at the following with respect to the study of this topic.
DEFINITION OF TERMS
Groundwater: This is the water found on the surface, subsurface existing in the soil pore spaces and in the fracture of rock formation.
Aquifer: Units of rock or unconsolidated deposit is called aquifer when it can yield a usable quantify of water.
Runoff: A fine portion of rainfall that makes its way towards rivers, ocean etc as surface and subsurface flow.
Water Table: The depth in the soil at which soil pore spaces, rock crevices becomes completely saturated with water.
Water Cycle: Water exist in nature both underground, in rivers, ocean and in the atmosphere which builds up as cloud by simple evaporation. When rain falls, some are trapped by vegetation as the rain drop may not be heavy. But gets to the ground surface if heavy and culminate surface flow. In continuum, they experience runoff and are stored up in surface depressions but very large quantity of the flow infiltrate into the deep soil through various soil arrangement to the aquifer layer underneath the ground. Water within the saturated zone flows under the influence of
hydraulic situation in an area following the minimum allowable gradient of that area rock strata. This flow is described as groundwater flow.
This correlation and interaction between ground water and water in the atmospheric is known as water cycle.
The figure below shows a typical water cycle and resource process of groundwater.
CHARACTERISTICS OF GROUNDWATER
Water in natural existence has potential (instinct at which usefulness can be extracted), storage which can be recharged. These values are what I classify as water characteristics.
Let us now examine these characteristic of groundwater taking Nigeria our country as case study in this presentation.
GROUND WATER STORAGE
Natural water whether as surface or underneath the earth is stores considerably as depression storage and to large quantity in sedimentary rock basins respectively. This cover some 50% of the country land mass.
On sedimentary deposits, groundwater resource occurs either as confined aquifers or unconfined aquifers with thickness varying from 15 to 100m (Nwaogazie 2009). Below is the table showing static ground water storage in Nigeria.
Summary of the total water resources in Nigeria.
|TWRS||Percentage||Cubic meter (m3)|
|Rain||Atmospheric water||3.08||1117 x 109|
|Surface||Fresh water||Fresh surface||0.03||12 x 109|
|Ground water||Salty groundwater||65.66||23.772 x 109|
|Total water in Nigeria||100%||36,202 x 109|
(Source: Schoeneich 2005)
As earlier stated, potential is the knowledge of the instint at which usefulness can be extracted. There are large ground water potential in Nigeria, far greater than the surface water resources estimated to be 224 Trillion litres per year (Hanidu 2009). RijsWlk (1981) estimated ground water resources at 0-50m depth in Nigeria to be 6 x 1018m3 (6 x 10km3).
However, from the eight aquifers in Nigeria (Akujieze, et al 2008), the Ajali sandstone aquifer yields 7-10 litres per second, the Benin formation (Coastal plain sands) aquifer yields 6-9litres per sec; the upper-aquifer 2.5-30l/s, the middle aquifer 24-32l/s, the lower aquifer with yields 10-35L/S of the Chad formation, the Gwandu formation aquifer yield of 8-15l/s and the crystalline fluvio-volcanic aquifer with a 15l/s yield in Jos plateau region, groundwater occurrence is not limited to only 50m below ground level.
These eight mega regional aquifers have an effective average thickness Rnage of 360m with a thickness range from 15-3,000m at a depth range of 0-630m below ground level with average depth of 22cm (Akujieze at al 2003). The potential annual groundwater resource are estimated at 5.93 x 103m3, out of which the sedimentary basin account for 67% (FMWRRD).
Why have water management? The reason for water management is to provide safe and efficient drinking water for the teaming world population under basic sanitation.
Groundwater pollution is the process of making water inside the earth dirty and unfit for use. The major sources of this pollution ((pollutants) are: indiscriminate defecation, lack of underground sewerage system, unlined opened drains carrying domestic wastes and evacuation into water bodies, refuse heap bearing toxic and biowaste materials. These and order factors leads to water management.
Globally, efforts are being made in respect of sustainable management of water resources. The world water forum, the world water commission, the Earth sunmit as well as water related projects of global water partnership, World bank, WHO, Food and Agricultural Organization (FAO), UNICEF, UNESCO, UNDP etc have been at the forefront in the timely efforts of water resource management in Nigeria especially in the provision of safe and potable drinking water which is within the frameworks of the united Nations millennium development Goals (MDG’s).
In the early 1950s, government’s attempt at groundwater development in Nigeria was through the geological survey of Nigeria. But concerted efforts have been made since independence towards providing portable water to the citizenry in 1962 and 1963, Nigerian government had its major intervention in water resource development plan which saw the establishment of the River Niger and lake Chad Basin commissions.
The Sokoto Rima and Chad Basin Authorities were established between 1973 and 1974. In 1975, the river basin authorities were increased to Eleven (11) having creasted the Federal Ministry of Water Resources (FMWR) in 1975. This saw through the embankment of extensive water resources development (both surface and under groundwater) to boosting economic activities such as irrigation, fisheries as well as hydropower generation the huge success recorded in all these effort were aimed at improving water supply delivery in line with the United Nations International Drinking water supply and sanitation Decade. (IDWSSD, 1981 to 1990).
Despite these efforts, the Federal Government carried out numerous intervention progreammes in the water sector including the National Borehole project (1980), Department for Food, Roads, and Rural Infrastructures (DFRRI 1986 to 1994), Rural water supply project (1995 to 1999), improved National Access to water supply (1999) and the senate constituency water projects (2001 till date).
The above listed bodies, organization and Federal Government Agencies have been in place managing water and water resource sustainability in the country which have been faced with gruesome impediments leaving the citizenry to facing good water supply shortage.
The occurrence of ground water is greatly influenced by the local geological conditions which ultimately control yield (the geological conditions refered here includes soil aquifer arrangement as affected by temperature and pressure of the earth crust). Recharge therefore to aquifers which influences the safe yields of wells, depend ultimately controls the amount of groundwater recovered from wells in any given locality (Offodile, 1979).
Reverse pumping from borehole also encourages recharge of groundwater.
Problems of Sustainable Groundwater Management
This is a major issue with a maintained trend using, Nigeria as case study. Generally, the Nigerian water problem revolves round two critical issues, namely,
- Inadequate access or poor distribution of water resources in time and space in relation to the needs of the people.
- Independent planning and management of these resources.
- Establishment of institution and rival agencies with overlapping functions. The above enumerated problems have manifested themselves in the form of
- Regular water shortages,
- Poor access to water supply which leads to water-borne diseases.
- Poor environmental quality causing groundwater pollution,
- Improper distribution of public wells due to lack of water well statistics,
- Poor maintenance and often sabotage in the development and operational process of public wells.
As stated by Ajayi et al (2008), Ajayi (2006), Ezeigbo (2008), Goni (2006) Hanidu (2003), Nwankwoala and Mmon (2008), Nwankwoala (2009), Offodile (2003, 2006), Oyebande (2006), Oteze (2006), Tijiami (2006), the major impediments to groundwater management includes:
- Absence of or ineffective legal/institutional and regulatory framework
- Poor maintenance culture,
- Poor technical and institutional capacity
- Lack of coordination
- Multiple program
- Lack of data and information for planning
- Shortage of well trained and committed manpower with appropriate technology
- Irregular recruitment and limited manpower occasioned by the civil-service structure
- Overbearing bureaucratic control by the supervising ministries.
- Lack of professional input on water programme and projects.
- Absence of professionalism due to politics
- Lack of community participation
- Inadequate revenue generation by water agencies
Suggested ways of Improving groundwater resources.
To profile sustainable portable water supply, it become so pertinent that personnel involved in water management must have good understanding of the hydrogeological controls that govern the behaviour and yield of ground water.
Maintenance of machines, wares etc for water movement must be at top echelon in the management agenda. Review policies to favour water distribution so to reach the common man. Lead campaign to check contamination level of ground water should be encourage.
Since groundwater is the recipient to all land based pollution, there is the need to protect groundwater from further degradation and depletion by embarking of urban, rural and community man literally progremma on pollution prevention and control.
The success of future portable water reaching the entire citizenry starts now for any groundwater scheme to succeed. Moreso, there should be effective policy framework. All stakeholders must be involve in their interdisciplinary approach towards sustainability of portable supply from groundwater.